Freelance Backend Software Engineer

Senior Backend Java Engineer (Freelance Contract) – Hungary

• Contract Length: 3+ Months
• Start Date: ASAP
• Day Rate: 120,000 HUF – 180,000 HUF per day
• Location: Hungary

About the Role

Beyond Sports is looking for an experienced Senior Backend Java Engineer to support the development, scaling, and modernisation of our high-performance backend systems and cloud infrastructure.

This is a hands-on freelance contract opportunity for a senior engineer with deep Java expertise, strong cloud experience, and a passion for building resilient, scalable systems. You’ll work closely with cross-functional engineering teams to refactor core microservices, improve system architecture, and ensure low-latency integrations across our web and mobile platforms.

Key Responsibilities

Design, refactor, and maintain scalable backend microservices and REST APIs using Java and Spring Boot

Re-architect existing backend systems to optimize for maintainability, reliability, and throughput

Implement secure identity, secrets management, and authentication standards across cloud environments

Integrate third-party systems, including real-time sports data feeds, video streams, and commentary providers

Deploy and manage containerised services using Docker and Kubernetes

Provision and maintain cloud infrastructure using Infrastructure as Code (IaC) tools like Terraform

Build, automate, and manage deployment workflows using modern CI/CD pipelines

Monitor, troubleshoot, and optimize application and database performance

Participate in technical planning, architectural discussions, and peer code reviews

Produce clear, maintainable technical documentation for APIs and core backend systems

Required Skills & Experience

Essential

Strong commercial contracting experience with Java and Spring Boot

Proven background building, deploying, and maintaining applications in production cloud environments ( AWS or Azure )

Hands-on experience with containerisation and orchestration using Docker and Kubernetes

Expertise in designing and building secure, high-traffic RESTful APIs

Practical experience writing Infrastructure as Code using Terraform

Solid working knowledge of relational and NoSQL databases (e.g., PostgreSQL , MySQL , DynamoDB , Cosmos DB )

Deep understanding of cloud security fundamentals (IAM, secrets management, key vaults)

Experience setting up and maintaining CI/CD pipelines (e.g., GitLab CI , Bitbucket Pipelines , or ArgoCD )

Desirable

Experience with event-driven architectures using Apache Kafka or similar messaging systems

Prior exposure to performance tuning and cloud cost-optimisation strategies

Strong automated testing practices (unit, integration, and regression testing)

Understanding of cloud networking components (VPCs/VNets, API Gateways)